On 25 April 1185, the Battle of Dannoura was fought in Japan between the Minamoto under Minamoto Yoshitsune against the Taira under Taira Tomomori during the Gempei War.
Why did it happen?
The origins of the Gempei War can be traced back to the decline of the Fujiwara clan in the twelfth century. In 1156, the Hojo Rebellion flared up between the Minamoto and Taira clans which reduced the Fujiwara to the role of figureheads. The triumph of the Taira clan in 1160 led to the execution of many Minamoto rivals, and in 1180, the Minamoto declared war against the Taira. At first, the Taira had the better of the conflict, defeating Minamoto Yorimasa at the Battle of Uji. However, after the Taira were defeated at the Battle of Kurikara in 1183, the war turned in favour of the Minamoto clan and the Taira were forced back towards their home territory around the Inland Sea. In 1185, Minamoto Yoritomo captured Taira’s main fortress of Yashima, forcing the Taira clan to escape via their ships towards the Shimonoseki Strait, where the decisive battle of the war was fought.
Who was involved?
The Minamoto navy at Dannoura numbered 850 warships, all oared galleys carrying samurai armed with bows, swords, and daggers. The Minamoto fleet was arrayed in a single line abreast, facing the entrance to the Shimonoseki Strait. The Taira fleet numbered 500 warships. Despite being outnumbered, the Taira navy had the advantage of familiarity with local weather and tides. The Taira fleet was divided into three divisions of 150 warships each, with 50 warships in reserve under Miura Yoshizumi. The Taira plan at Dannoura was to wait for the ebb tide to flow in mid-morning to aid their oarsmen in surrounding the Minamoto navy and engaging their crews in close-quarters fighting.
What happened?
On 25 April, both sides began the battle by exchanging long-range arrow fire. Due to the ebb tide flowing from the Shimonoseki Strait, the Taira gained the initiative in the encounter. Subsequently, Taira Tomomori used his superior knowledge of naval tactics and tidal conditions to sail his fleet towards the Minamoto navy and attempt to surround it. As both fleets intermingled, the samurai on the galleys engaged each other in hand-to-hand combat with their swords and daggers. However, at 11am, the tide changed and began to flow westward out of the Shimonoseki Strait, causing the Minamoto fleet to gain the upper hand in the battle. At that point, the Taira admiral, Miura Yoshizumi, betrayed Taira Tomomori and attacked his fleet in the rear. After realising the battle was lost, many Taira, including Emperor Antoku and his grandmother Nii Dono, committed suicide by jumping into the sea.
What changed as a result?
The Battle of Dannoura was a decisive Minamoto victory. In the aftermath of the battle, several Taira leaders were fished out of the sea and taken back to Kyoto for execution. In 1192, Emperor Go-Toba gave Minamoto Yoritomo the title of shogun, or “supreme commander.” The Kamakura shogunate would rule Japan until 1333, when the Japanese emperor Go-Daigo overthrew the shogunate and re-established Imperial rule over Japan. However, after the Battle of Minatogawa in 1336, the Ashikaga clan restored the shogunate, and it would not be until the Meiji Restoration of 1868 that the emperor was restored to power. Another legacy of the Gempei War was its impact on the military culture of Japan. Traditions and values like seppuku and bushido would inform the military mindset of Japanese soldiers and generals during the twentieth century, particularly during the Second World War.
Bibliography
David, Saul. War: The Definitive Visual History. New York, Dorling Kindersley, 2009.
Clements, Jonathan. A Brief History of the Samurai: The Way of Japan's Elite Warriors. London, Constable & Robinson, 2010.
Grant, R.G. Battle: A Visual Journey Through 5,000 Years of Combat. London, Dorling Kindersley, 2005.
Grant, R.G. Battle At Sea: 3,000 Years of Naval Warfare. New York, Dorling Kindersley, 2008.